Referring now to FIG. 1, a functional block diagram of an engine system is presented. Air enters through an air filter 102, which may include a mass airflow meter or other sensors (not shown). The air continues through the intake inlet side of a turbocharger 104 where the air may be compressed. Upon exiting, the air may pass through an air cooler 106 or other conditioners before it enters an intake manifold 108. As the air enters the intake manifold 108, exhaust gases may be recirculated via an exhaust gas recirculation (EGR) valve 110 to create an air mixture. The EGR valve 110 may be positioned by an EGR positioning module 112.
Once the air mixture reaches the intake manifold 108, it may be combined with fuel from a fuel injector 114 in a cylinder 116 to produce positive torque. The engine system may include multiple fuel injectors 114 and cylinders 116. Exhaust gases exit the cylinder 116 through an exhaust manifold 118 and enter an exhaust inlet side of the turbocharger 104. The turbocharger 104 may be used to increase mass airflow and/or intake manifold pressure. Increased mass airflow and intake manifold pressure may allow for increased drive torque. Exhaust gases may flow through a catalyst 120 or other exhaust treatment components. A particulate filter 122 collects particulate matter from the exhaust gases before the gases are released to the atmosphere.
An engine control module 124 controls operation of the engine system in various operating modes. The operating mode may be determined by various factors including driver input and other vehicle demands.
For example, it may be necessary to remove the particulates from the particulate filter 122 by oxidizing the particulates. The engine system may achieve oxidization of the particulates at elevated exhaust gas temperatures. Exhaust gas temperatures may be increased by controlling the air/fuel mixture in the engine system by altering the output of the fuel injector 114.
The engine system may also provide engine braking, which uses pumping losses and/or frictional losses to slow the vehicle. Fuel injector 114 may be cut off so that only air flows through the engine system. Air pressure inside the cylinders 116 may slow the engine and therefore the vehicle.